The present invention relates to an automatic performing apparatus. More particularly, the present invention relates to an automatic performing apparatus which can prevent damage to the apparatus caused by software and hardware malfunctions, by cutting off the power supply to a recording and/or reproducing devices.
A conventional automatic performing apparatus comprises a CPU for generating electrical signals which serve as instructions controlling the start, key stroke intensity, and end of each key stroke and key actuators which typically include solenoids for converting electrical energy from a power source into mechanical energy according to the instructions from the CPU. A performance is, therefore, conducted by the actuators executing performance instructions from the CPU.
Occasionally, a solenoid activated upon an activation instruction from the CPU cannot be de-activated even after the CPU has given a de-activation instruction in such a conventional automatic performing apparatus. This happens when the de-activation instruction is not executed due to various causes including noise over-riding or canceling the instruction. If a solenoid receives excessive energy or does not receive a de-activation instruction, it may be overheated and, in the worst case, permanently damaged.
This problem has been often dealt with by giving another de-activation instruction if a solenoid has been activated for too long a time period. More particularly, a memory provided in the apparatus has data of time during which solenoids are allowed to be activated. This solenoid activation time is set slightly longer than the actually necessary time for sufficiently activating solenoids. Therefore, if a solenoid is still activated after the solenoid activation time indicated in the above data stored in the memory, the CPU gives another instruction to deactivate the solenoid.
Since this method attempts to solve the problem in software, it is only workable if a solenoid is not deactivated due to noise, but not workable if the CPU itself malfunctions or stops executing instructions.